Question

We are noticing some permanent marks etched onto various glass parts we use in lighting products that cannot be removed. These appear regardless of the type of water (tap, DI etc. Our DI water is purified to 2us/cm).

No matter the amount of rubbing with IPA or micro-fibre cloth, we cannot remove them, so it seems to be etched.

Is there some process going on here where water can somehow etch / eat the glass? Something else that we are not aware of?

Answer 1

Etching of glass can occur due to the gradual dissolution of the glass. The marks that cannot be removed may be a result of this etching process. Impurities in water, even purified water, can contribute to glass etching.

Step-by-step explanation:

Etching of glass is a slow process that involves the gradual dissolution of the glass. The marks that are etched onto the glass parts in the lighting products may be a result of this process. Glass can be etched by certain chemicals, such as hydrofluoric acid or ammonium bifluoride. These chemicals dissolve the glass under them, creating permanent marks that cannot be removed.

Water alone is usually not enough to etch the glass, but impurities in the water can contribute to the etching process. Even purified water, like DI water, can contain impurities that react with the glass and cause etching. These impurities could come from the environment or from the process of making the water safe to drink. However, without further information about the specific glass parts and the water being used, it is difficult to determine the exact cause of the etching marks.

To prevent further etching, it is important to avoid contact between the glass parts and any chemicals that can dissolve glass. Using appropriate cleaning methods and products, such as soft cloths and mild glass cleaners, can help maintain the appearance of the glass parts.